Term
Seizure Disorders
Epileptic seizures |
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Definition
-synchronous activation of many neurons
-self-limiting |
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Term
Seizure Disorder
Epileptic disorder or epilepsy |
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Definition
-recurrent epileptic seizures
- most common neuro problem |
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Term
Types of Epilepsy
Idiopathic |
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Definition
No ID cause
Genetic and Age dependent
Therapy for life |
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Term
Types of Epilepsy
Symptomatic |
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Definition
Intracranial (brain tumors, encephalitis)
Extracranial (toxins, metabolic disorders) |
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Term
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Definition
May require:
-no tx, if freq is low (<1/mth)
-one drug
-multiple drugs |
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Term
| Objectives of drug therapy |
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Definition
-reduction in freq and intensity while avoiding side effects
-reduce freq by at least 50% |
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Term
| Ideal Characteristics of AED |
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Definition
-non-sedating
-safe and effective
-high bioavailability
-long half life |
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Term
| Question from him: Which among the following would you consider least ideal characteristic for an AED? |
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Definition
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Term
| Question from him: Which of the following is a common objective for the long-term tx of idiopathic epilepsy in dogs? |
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Definition
| Reduction in freq of seizures by 50% or more |
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Term
| Principle of Antiepileptic Therpay |
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Definition
-therapeutic range
-elimination T(1/2)
-owner compliance
-side effects
-drug interactions
-avoid seizure prone drugs |
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Term
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Definition
-CHRONIC TX
-Acts on GABA
-Decreases release of neurotransmitters by decreasing influx of Ca
-Stabilizes post-synaptic neurons |
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Term
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Definition
-oral absorption slow
-long half-life
-Peak [plasma] 4-8 hrs post tx
-wide distribution
-HEPATIC METABOLIZATION
-ss in 2-3 weeks |
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Term
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Definition
Sedation/Polyphagia (at first)
Hepatotoxicity, hypothyroid, blood dyscrasias |
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Term
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Definition
-Phenobarb induces its own metabolism (adjust dose after a while)
-trough (to make sure its still at therapeutic levels)
-peak (if toxicity suspected) 4-6 hrs after given |
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Term
| Question by him: Which of the following is true about phenobarb? |
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Definition
| It is better for chronic than for acute treatment |
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Term
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Definition
-Add-on of choice in dogs
-Stabilizes neuronal cells by hyperpolarization (accumulation of Bromide)
-CONTRAINDICATED in renal failure
-Br and Cl compete for renal reabsorption |
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Term
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Definition
-well-absorbed (peak 1.5 hrs)
-KIDNEY ELIMINATION
-1/2 life is 24 days (Dogs)
-1/2 life is 1-2 wks (Cats)
-when SS is reached, phenobarb dose can be reduced or elim |
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Term
KBR (his question)
What is the most common side effect assoc with KBr use? |
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Definition
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Term
KBr (his question)
What is the most appropriate way to deliver a loading dose of KBr |
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Definition
| Divided into several daily doses (3-5) |
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Term
| Diazepam (Valium) Factoids |
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Definition
-increases the action of GABA on nerve cells
-First choice in status epilepticus (acute)
-SECOND CHOICE for CHRONIC (cats) |
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Term
| Diazepam (Routes of Admin) |
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Definition
-IV (emergency)
-CRI
-Intranasal
-per rectum (at home) |
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Term
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Definition
-low oral availability in dogs
-variable elim
-NOT APPROPRIATE for LONG term use in dogs |
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Term
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Definition
- add-on
- well tolerated in dogs/cats
- oral bioavailability in dogs is 100%
- serum 1/2 life is 3-4 hrs
- elimination in urine
- high margin of safety
- FIRST CHOICE as add on for CATS
- Binds to synaptic vesicle protein in brain to prevent neurotransmitter release |
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Term
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Definition
-metabolized to phenobarb
-$$$ |
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Term
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Definition
-low tox potential
-DOES NOT CAUSE SEDATION
-liver dysfxn potential side effects |
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Term
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Definition
-focal and generalized seizures
-adjunct or monotherapy
-little experience in CATS |
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Term
2nd generation AEDS
MOA: Sodium Channels |
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Definition
-initiate action potential in neurons
-inactive during refractory period
-drugs stabilize the inactive config preventing neuronal firing |
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Term
2nd generation AEDs
MOA: Low voltage Ca channels |
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Definition
-"pacemakers" of normal rhythmic brain activity
-generalized seizures
-drugs lock these channels inhibiting slow depolarizing currents |
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Term
2nd generation AEDs
MOA: GABA-A receptors |
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Definition
-GABA increases intracellular Cl
-hyperpolarization (no action potential) |
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Term
2nd generation AEDs
MOA: Glutamate receptors |
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Definition
-Na and Ca influx
-K efflux |
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Term
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Definition
-MOA not well known
-increases of concentration of GABA in neurons
-inhibit neuronal Na and Ca channels
-eliminated in urine
-eliminated in hepatic metabolism
- 1/2 life 3-4 hrs |
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Term
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Definition
-focal and generalized seizures in people
-mainly eliminated by liver
-BID as monotherapy
-much higher drug clearance in dogs receiving PB |
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Term
Zonisamide
Efficacy in dogs with refractory epilepsy |
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Definition
-seizure freq decreased by 93%
-side effects: transient sedation, ataxia, vomiting |
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Term
| Cluster Seizures & Status Epilepticus |
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Definition
-Diazepam IV first choice
-Pento/Phenobarb (15-20 min onset)
-Propofol (rapidly acting and quickly metabolized/ admin slowly to avoid apnea)
-Etomidate
-Levetiracetam IV |
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